Strict regulation of electronic cigarettes isn't warranted based on current evidence, a team of researchers says.

On the contrary, allowing e-cigarettes to compete with regular cigarettes might cut tobacco-related deaths and illness, the researchers concluded after reviewing 81 prior studies on the use and safety of the nicotine-emitting devices.

"Current evidence suggests that there is a potential for smokers to reduce their health risks if electronic cigarettes are used in place of tobacco cigarettes and are considered a step toward ending all tobacco and nicotine use," said study researcher Thomas Eissenberg, co-director of the Center for the Study of Tobacco Products at Virginia Commonwealth University in Richmond.

The study, partly funded by the U.S. National Institutes of Health, was published July 30 in the journalAddiction.

Whether e-cigarettes should be regulated, and how strictly, is being debated by regulatory agencies around the world. Several medical organizations have called for restrictions on use of the increasingly popular devices.

Although long-term risks of e-cigarettes remain unknown, the new study concluded the benefits of e-cigarettes as a no-smoking aid outweigh potential harms.

"If there are any risks, these will be many times lower than the risks of smoking tobacco," said senior author Dr. Hayden McRobbie, from the Wolfson Institute of Preventive Medicine at Queen Mary University of London.

"We need to think carefully about how these products are regulated," he said. "What we found is that there is no evidence that these products should be regulated as strictly as tobacco, or even more strictly than tobacco."

No evidence has shown that the vapor produced by e-cigarettes is harmful to users or bystanders in contrast to cigarette smoke, he added. It's not the nicotine in cigarettes that kills people, he said. (Nicotine is the addictive agent in cigarettes).

"Use of e-cigarettes by people who don't smoke is very rare," McRobbie said. Furthermore, there is no evidence to support arguments that e-cigarettes are a gateway to smoking tobacco, he added.

"There is evidence that e-cigarettes enable some users to quit smoking or reduce their consumption," McRobbie said. "If there is evidence that e-cigarettes reduce smoking-related harm, then they need to be easily obtainable and not regulated more strongly than tobacco products."

Dr. Norman Edelman, a senior medical consultant for the American Lung Association, disagrees. The U.S. Food and Drug Administration should have authority over all tobacco products and e-cigarettes, said Edelman, a professor of medicine and physiology and biophysics at the State University of New York at Stony Brook.

"It is imperative that the FDA finalize proposed e-cigarette regulations by the end of 2014," he said. "The FDA needs to crack down on quit-smoking and other health claims that e-cigarette companies are making," Edelman said.

Edelman said it's too soon to know if e-cigarettes will cause long-term damage. "So far there hasn't been very much chronic use of e-cigarettes. So it's not possible to say there will be no harm," he said.

"Since we are talking about a recreational drug -- it's not essential to life, it doesn't cure any illness -- it would only make sense to regulate it rigorously until we find out whether it's good or bad," Edelman said.

Earlier this month, the Forum of International Respiratory Societies, which includes more than 70,000 members worldwide, urged governments to ban or limit e-cigarettes until more is known about their health effects.

And this month, the American Medical Association requested tighter restrictions on the sale and marketing of e-cigarettes.

The AMA's recommendations include a minimum age of purchase; childproof packaging; restrictions on flavors that appeal to young people, and a ban on unsupported claims that the devices help people quit smoking.

Preventing the marketing of e-cigarettes to minors is another priority, the medical association says.